RNA interference is ineffective as a routine method for gene silencing in chick embryos as monitored by fgf8 silencing.

The in vivo accessibility of the chick embryo makes it a favoured model system for experimental developmental biology. Although the range of available techniques now extends to miss-expression of genes through in ovo electroporation, it remains difficult to knock out individual gene expression. Recently, the possibility of silencing gene expression by RNAi in chick embryos has been reported. However, published studies show only discrete quantitative differences in the expression of the endogenous targeted genes and unclear morphological alterations. To elucidate whether the tools currently available are adequate to silence gene expression sufficiently to produce a clear and specific null-like mutant phenotype, we have performed several experiments with different molecules that trigger RNAi: dsRNA, siRNA, and shRNA produced from a plasmid coexpressing green fluorescent protein as an internal marker. Focussing on fgf8 expression in the developing isthmus, we show that no morphological defects are observed, and that fgf8 expression is neither silenced in embryos microinjected with dsRNA nor in embryos microinjected and electroporated with a pool of siRNAs. Moreover, fgf8 expression was not significantly silenced in most isthmic cells transformed with a plasmid producing engineered shRNAs to fgf8. We also show that siRNA molecules do not spread significantly from cell to cell as reported for invertebrates, suggesting the existence of molecular differences between different model systems that may explain the different responses to RNAi. Although our results are basically in agreement with previously reported studies, we suggest, in contrast to them, that with currently available tools and techniques the number of cells in which fgf8 gene expression is decreased, if any, is not sufficient to generate a detectable mutant phenotype, thus making RNAi useless as a routine method for functional gene analysis in chick embryos

The relationship between income, health status, and health expenditures in the United States

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. [29]).The relationship between income and health has important implications for policy makers and businesses, and will continue to receive attention as healthcare reform takes hold in the U.S. Most existing literature looks at the relationship between income and either health status or health expenditures in isolation. However, in this research, we take advantage of the wealth of data available in the U.S. Department of Health and Human Services' Medical Expenditures Panel Survey (MEPS) to answer two important, related questions regarding the income-health relationship for U.S. adults. First, we seek to determine how much sicker are poorer people than richer people (if at all), both in their perception and in actual terms. Second, we seek to determine if a poorer person is likely to consume more or less care than a richer person for given level of health or condition. To answer the first question, we start by examining the relationship between family income and health status using multiple regression techniques. For both perceived health and actual health, we find a curvilinear relationship between income and health, with diminishing returns associated with membership in successively higher-income groups. Depending on the status metric, the associated health benefits of membership in highincome cohorts tend to flatten once income reaches approximately 500-600% of the federal poverty level (FPL). We also find that marginal income at low income levels tends to be more strongly associated with reduced probability of poor health than increased probability of strong health. Regardless of the dependent variable chosen, we find that the shape of the relationship between income and health status is the same once we normalize the coefficients. Perceived and actual health are strongly related, although some of our results indicate that poorer people may be more pessimistic about their health than richer people. We find similar trends when we examine the relationship between income and health expenditures using the MEPS data. In this case, however, the diminishing returns associated with membership in higher-income cohorts are more accelerated, and the associated reductions in spending for membership in successive cohorts above 200-300% FPL are not significantly different from zero. When we add controls for health status, however, we find that the wealthiest members of the population are most likely to have the highest spending on healthcare, although not drastically so. In addition, we find the poorest members of the population do not have a tendency to overconsume care relative to their level of health.by David Bueno.M.B.A

De la sexosfera al sexe intel·lectual. Una visió transversal d’un fenomen universal

All known living beings share features such as how genetic material is organized into DNA, pointing directly to a common evolutionary origin of all life on Earth. All current species originated from an ancestral organism by evolutionary mechanisms. The environment in which life develops is dynamic and changing, forcing all species to adapt constantly. One of the ways to adapt is through sex, or through sexual phenomena. Sex is essential to life, inherent to vital processes. This paper, based on several groundbreaking books published by the author, will discuss what sex is and its evolutionary importance for the survival and adaptation of the species. Its universality and inseparability from life leads to the proposal and justification of the existence of a sexosphere, the layer of the Earth that is characterized by the existence of sex. In the case of the human species, this paper also proposes the existence of a new type of sex: intellectual sex.Tots els éssers vius coneguts comparteixen algunes característiques, com ara la manera d’organitzar el material genètic en l’ADN, la qual cosa assenyala directament cap a un origen evolutiu comú de tots ells. A partir d’un organisme ancestral, per evolució, s’han originat totes les espècies actuals. El medi on es desenvolupa la vida és dinàmic i canviant, la qual cosa obliga totes les espècies a adaptar-s’hi constantment. Una de les maneres que tenen d’adaptar-se és a través del sexe, o de fenòmens sexuals. El sexe és consubstancial a la vida, inherent als processos vitals. En aquest article, que es basa en diversos llibres publicats per l’autor on es fan aportacions noves sobre el tema, es parla de què és el sexe i de quina importància evolutiva té, per a la supervivència i l’adaptació de les espècies. La seva universalitat i indisociabilitat amb la vida fan que es proposi i es justifiqui l’existència d’una sexosfera, la capa de la Terra que es caracteritza per l’existència de sexe. I, en el cas de l’espècie humana, que es proposi també l’existència d’un nou tipus de sexe, el sexe intel·lectual

The magnetic field configuration of a solar prominence inferred from spectropolarimetric observations in the He I 10830 A triplet

Context: The determination of the magnetic field vector in quiescent solar prominences is possible by interpreting the Hanle and Zeeman effects in spectral lines. However, observational measurements are scarce and lack high spatial resolution. Aims: To determine the magnetic field vector configuration along a quiescent solar prominence by interpreting spectropolarimetric measurements in the He I 1083.0 nm triplet obtained with the Tenerife Infrared Polarimeter installed at the German Vacuum Tower Telescope of the Observatorio del Teide. Methods. The He I 1083.0 nm triplet Stokes profiles are analyzed with an inversion code that takes into account the physics responsible of the polarization signals in this triplet. The results are put into a solar context with the help of extreme ultraviolet observations taken with the Solar Dynamic Observatory and the Solar Terrestrial Relations Observatory satellites. Results: For the most probable magnetic field vector configuration, the analysis depicts a mean field strength of 7 gauss. We do not find local variations in the field strength except that the field is, in average, lower in the prominence body than in the prominence feet, where the field strength reaches 25 gauss. The averaged magnetic field inclination with respect to the local vertical is 77 degrees. The acute angle of the magnetic field vector with the prominence main axis is 24 degrees for the sinistral chirality case and 58 degrees for the dextral chirality. These inferences are in rough agreement with previous results obtained from the analysis of data acquired with lower spatial resolutions.Comment: Accepted in A&

A-term inflation and the MSSM

The parameter space for A-term inflation is explored with $W=\lambda_p \phi^p/(p M_P^{p-3})$. With p=6 and \lambda_p~1, the observed spectrum and spectral tilt can be obtained with soft mass of order 10^2 GeV but not with a much higher mass. The case p=3 requires \lambda_p~10^{-9} to 10^{-12}. The ratio m/A requires fine-tuning, which may be justified on environmental grounds. An extension of the MSSM to include non-renormalizable terms and/or Dirac neutrino masses might support either A-term inflation or modular inflation.Comment: 10 pages, 3 figures; Comments added, typos correcte

Evolución del rendimiento de un motor de combustión interna. Aplicación a pistones

El projecte que presentem a continuació té com a finalitat el disseny i elecció d’un procés de fabricació del pistó, per millorar el rendiment d’un motor de combustió interna. Per aconseguir el nostre objectiu es necessari dividir el projecte en tres blocs: explicació d’un motor de combustió interna, disseny i procés de fabricació del pistó, elecció d’un pistó per millorar el rendiment i pressupost. Respecte a la primera part del projecte, l’explicació es necessària per saber com funciona un motor i la funció que té el pistó. Una vegada sabem que és un pistó i el treball que ha de realitzar, es passarà a la segona part del projecte que es el disseny i procés de fabricació del pistó. D’ aquesta manera podrem saber que característiques i propietats ens poden oferir. L’ elecció d’un pistó per millorar el rendiment, es una conclusió que aporta tots els coneixements dels processos de fabricació y disseny. Com a quarta part s’ inclourà un pressupost complet del projecte, des de l’estudi fins el muntatge en un vehicle

On the feasibility of collaborative green data center ecosystems

The increasing awareness of the impact of the IT sector on the environment, together with economic factors, have fueled many research efforts to reduce the energy expenditure of data centers. Recent work proposes to achieve additional energy savings by exploiting, in concert with customers, service workloads and to reduce data centers’ carbon footprints by adopting demand-response mechanisms between data centers and their energy providers. In this paper, we debate about the incentives that customers and data centers can have to adopt such measures and propose a new service type and pricing scheme that is economically attractive and technically realizable. Simulation results based on real measurements confirm that our scheme can achieve additional energy savings while preserving service performance and the interests of data centers and customers.Peer ReviewedPostprint (author's final draft

La Necessitat de la biologia per a una formació integral en l'ensenyament secundari

Durant el procés d'aprenentatge, tots els coneixement s'han d'iniciar i han de tenir com a punt de referència central l'entorn més immediat del subjecte que participa d'aquest procés. Els humans som, per davant de tot, ens biològics que vivim submergits en una biosfera. A més, actualment estem vivint l'eclosió de l'aplicació de la biologia en la nostra vida diària, en temes tan diversos com la biotecnologia, l'ecologia, la biomedicina, l'alimentació i l'energia, entre molts altres. Això comporta que tots els ciutadans, tots els nostres estudiants, hagin de tenir un nivell mínim de coneixements biològics, adequats al seu nivell d'estudis. Actualment l'aprenentatge de la biologia en sentit ampli és obligatori des de l'educació infantil fins al final de l'educació secundària obligatòria. Però, per què no ho és al batxillerat, el qual serveix de base als estudiants de formació professional de grau superior i d'universitat? En aquest article es discuteix la imperiosa necessitat que l'aprenentatge de la biologia es mantingui també com a obligatori durant el batxillerat per a tots els nostres estudiants, independentment de la via que triïn, com ja ho era fa uns anys, per tal de proporcionar a les noves generacions de ciutadans i de professionals una formació integral adequada per a una societat canviant culturalment i tècnicamentDuring the learning process, all knowledge must begin from the immediate surroundings of the subject that participates in the process, who has to become the gravity point of the learning. We the humans are, first of all, biological beings who live within a biosphere. Moreover, we are currently living the hatching of the Biology applied to our daily life, in many subjects ranging from biotechnology to ecology, biomedicine, nutrition, and energy, among many others. This fact entails that all citizens, that all students, need to have a minimum level of biological knowledge, according to their academic degree. Nowadays the learning of Biology in broad sense is obligatory from the pre-school to the completion of the obligatory secondary education. But, why is it not obligatory during the bachelor’s degree, which must serve as the basis for the students involved in the superior degree of professional formation and the university? In this article, the urgent need that the learning of Biology become again obligatory during the bachelor’s degree for all the students is discussed, independently of the academic route they follow, as it was several years ago, aiming to provide the new generations of citizens and professionals an integral formation suitable for a culturally and technically ever changing society